Drilling Machines

Pregunta	Respuesta
Which variable is the most important when determining a spindle speed?	The diameter of the drill
Cutting speed refers to:	The rate at which the cutting edge of a tool moves through the metal measures in feet per minute
How fast should a 1/2" drill turn when drilling machine steel if the cutting speed (CS) is 90?	rpm=(cs x 4)/drill dia (90 x 4)/0.5=720 rpm
Do small drills require a higher feed per revolution than larger ones?	Small holes require lower feed per revolution than large drills but turn at a higher rpm
Which abbreviate is used to express the feed rate on a drill press?	ipr (inch per revolution)
A drill press spindle has a #2 Morse taper. A twist drill with #3 Morse taper shank must be mounted in the spindle. How would you secure the drill in the spindle?	with a drill socket
To remove a tapered shank twist from the drill press spindle, use a ?	drill drift
Drill chucks may be mounted in the drill press spindle or a tapered shank by means of a ?	either a taper or a thread
V-blocks are used mostly on the drill press for:	holding round material
To clamp a workpiece correctly with a straight clamp:	you must bolt as close to the workpiece as possible
When using a sensitive drill press, what should you do as the drill breaks through the workpiece?	ease up on the cutting pressure so the drill doesn't grab the part.
If a drill wanders off centre, the best method to draw it back to centre is to use a :	diamond point chisel
The recommended drill size to ream a 3/8" hole on a drill press is:	23/64" 1/64" smaller than the reamer
The included point angle of a countersunk hole for most flathead screws is:	82 degrees
Which type of machine tap will push the chip out ahead of the tap:	spiral point tap
The lip relief (clearance) angle on a drill should be:	between 8 to 12 degrees
A general purpose drill bit for drilling most metals has an included point angle of:	118 degrees
Carbide drills may be operated at a cutting speed how many times faster than high speed steel drills?	3 x faster
A drill which is ground with lips of unequal length, will drill a hole which is:	an oversize hole will be drilled because cutting will only be done on one of the cutting edges.
Define drilling	the operation of producing a hole using a tool called a twist drill
Define boring	the operation of truing and enlarging a hole by means of a single point cutting tool, usually held in a boring bar
Define reaming	the operation of sizing and producing a smooth round hole from a previously drilled or bored hole with the use of a cutting tool having several cutting edges
What is the difference between spot-facing and counterboring?	spot facing - smoothing and squaring the surface around a hole to provide a a seat for the head of a cap screw or nut. counterboring - enlarging the top of a previously drilled hole to a given depth to provide a square shoulder for a bot or capscrew.
State two methods by which the size of a drill press may be determined.	- the distance from the center of the spindle to the column of the machine - the diameter of the largest circular piece that can be drilled in the center
Compare a sensitive drill press with an upright drilling machine.	sensitive drill press - only one hand feed machanism so the operator can "feel" how the drill is cutting. Generally light, high speed machines. upright drilling machine - larger and heavier. gearbox to provide greater variety of speeds. - 3 methods to advance splindle, hand lever, handwheel and automatically. - table may be raised or lowered - coolant reservoir on some models
Describe and state the purpose of the following parts of a sensitive drill press: base	provides stability for the machine, and rigid mounting for the column
Describe and state the purpose of the following parts of a sensitive drill press: column	- table is mounted to column and can be adjusted to any point between the base and the head - drill press head is mounted to top of column
Describe and state the purpose of the following parts of a sensitive drill press: Drilling head	contains the mechanisms used to revolve the cutting tool and advance it to the workpiece
Describe and state the purpose of the following parts of a sensitive drill press: Table	used to support the workpiece
Describe and state the purpose of the following parts of a sensitive drill press: Depth stop	can be set to control the depth that the cutting tool enters the workpiece
What are the advantages of a radial drilling machine?	- larger and heavier work can be machined - drilling head can be easily raised or lowered - drilling head can be easily moved to any location - more power - head can be swiveled on universal models
Compare the construction of a radial drilling machine to that of a standard upright drill press,	larger and heavier
What is the purpose of a drill chuck?	to hold the straight shank cutting tool
Name four types of drill chucks.	key type keyless type precision keyless jacobs impact keyless
What is the purpose of a drill sleeve?	used to adapt the cutting tool shank to the machine spindle
What is the purpose of a drill socket?	used to adapt the drill when the hole in the machine spindle is too small for the taper shank of the drill
How is a tapered-shank drill removed from a drill press spindle?	with a drill drift
Name three types of drill vises and state the purpose of each.	drill vise - used to hold round, rectangular, square or odd shaped pieces for any drilling operation angle vise - allows drilling holes at an angle contour vise - special movable jaws that automatically adjust to odd shaped work pieces
What is the purpose of V-blocks?	to support round parts for drilling
What is the purpose of step blocks?	used to provide support for the outer end of the strap clamps
Describe an angle plate and state its purpose.	90 degree plate used to fasten work for drilling
What is the advantage of a drill jig?	eliminate the need for laying out hole locations
Why is it important that work be clamped properly for any machining operation?	so the part does not come loose
Define the body of a twist drill.	portion of drill between the point and the shank
Define the web of a twist drill.	Thin partition in the center of the drill that extends the full length of the flutes
Define the point of a twist drill.	The tip of the drill, consists of the chisel edge, cutting edge, heel and body clearance
State the purpose of the following parts: Tang	On the end of a tapered shank to prevent the drill from slipping while it is cutting and allows the drill to be removed without the shank being damaged
State the purpose of the following parts: Flutes	They form the cutting edges, admit cutting fluid and allow the chips to escape from the hole
State the purpose of the following parts: Margin	it is the narrow raised section on the body of the drill. its purpose is to provide a full size to the dill body and cutting edges
State the purpose of the following parts: Body clearance	it is the undercut portion of the body between the margin and the flutes. it is made smaller to reduce friction between the drill and the hole.
What is the purpose of the following drill points and what degree is it ground to: conventional	118 degrees general purpose drilling
What is the purpose of the following drill points and what degree is it ground to: long angle	60 to 90 degrees used for drilling non ferrous materials
What is the purpose of the following drill points and what degree is it ground to: flat angle	135 to 150 degrees used to drill hard and tough material
Why is it necessary to thin the web of a drill?	to reduce pressure and heat while drilling
List four systems of drill sizes and give the range of each.	Fractional drill sizes Number drill sizes Letter drill sizes Millimeter (metric) drill sizes
State the purpose of the high-helix drill	for drilling deep holes in aluminum, copper, die cast material and other material where the chips have a tendancy to jam in a hole
State the purpose of the Core drill	has three or four flutes. used to enlarge cored, drilled or punched holes.
State the purpose of the Oil hole drill?	has one or two oil holes to force oil to the cutting edge cooling the drill and forcing chips out
State the purpose of the Straight-fluted drill	for drilling soft materials like brass copper or plastic. straight flutes prevent the drill from drawing itself into the material while cutting
State the purpose of the gun drill.	used for producing holes as deep as 20ft
State the purpose of the hard-steel drill	used for drilling hardened steel
What problems generally result from the use excessive speed and excessive feed?	excessive speed = wear at corners of drill excessive feed = breakdown of chisel point and cutting edges/lips
Discuss excessive lip clearance and insufficient lip clearance.	excessive clearance = lack of support behind cutting edge insufficient clearance = causes drill to rub behind the cutting edge
What is the effect of drills with unequal angles on the cutting lips?	one cutting edge works harder than the other causing bellmouth holes and poor tool life
What is the effect of drills with cutting lips unequal length?	produces oversize holes
What are the characteristics of a properly ground drill?	both cutting lips should be same length both cutting lips should be same angle lips free from wear or nicks no sign of wear on the margin

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	Creado por Vincent Bergeron hace alrededor de 9 años